Digital subscriber line (DSL) technology has quickly emerged as a high quality solution for high speed Internet access. DSL can transmit both voice and data, including video data, simultaneously over an existing, single copper pair up to 18,000 feet long. Since DSL can utilize existing telephone lines, the service costs associated with DSL are relatively low for network providers and customers. Moreover, since data can be transmitted relatively quickly using DSL, it is a very attractive option for providing high-speed access to customers.
A traditional DSL architecture that is deployed in a Central Office or Street Cabinet (both referred to as CO), may include a Main Distribution Frame (MDF) that couples wire connections within the CO to connections exterior of the CO (e.g., DSL modems located at customer locations). A DSL Access Multiplexer (DSLAM) may be housed in the CO. The DSLAM may include one or more DSL linecards. The one or more DSL linecards may receive customer DSL connections and aggregate those connections onto one or more high-density connections coupled to the Internet. Each DSL linecard housed in the DSLAM may handle a predetermined number of customer DSL connections.
A legacy baseband switch for ISDN or Plain Old Telephone Service (both referred to as POTS) switch may also be deployed in the CO. The POTS switch may include one or more POTS cards. The one or more POTS cards may receive customer analog voice telephone signals for distribution to the Public Switched Telephone Network (PSTN). Each POTS card housed in the POTS switch may handle a predetermined number of customer analog voice telephone signals.
A splitter may be deployed between the MDF and the DSLAM and POTS switch. The splitter may include high-pass and low-pass filters. The high-pass filter distributes DSL signals to the DSLAM, where the low-pass filter distributes analog voice telephone signals to the POTS switch. The splitter may be incorporated into the DSLAM or POTS switch. For example, each DSL linecard may include the splitter. A plurality of splitters may be employed in COs that accommodate high DSL and analog voice traffic.
Recently, network providers have initiated the tedious and costly process of eliminating the POTS switch, in favor of implementing an all digital network that handles voice and data traffic. This all digital network is also known as All Digital Loop (ADL) in a related portion of the International Telecommunications Union (ITU) Standards. DSL internet traffic remains essentially unchanged in the ADL. However, instead of handling customer voice signals by way of a POTS switch and the PSTN, those signals are digitized and distributed over Internet protocol networks, such as the Internet. This digital voice delivery process is conventionally known as Voice over Internet Protocol (VoIP). Internet telephony is not limited to voice signals. Facsimile, voice-messaging and other related signals may also be distributed using the Internet.
Migrating from a traditional DSL architecture that is implemented with DSLAMs and POTS switches has proven to be difficult. One migration option involves replacing existing DSLAMs and POTS switches with ADL equipment capable of handing DSL internet traffic and digitized signals originating from customer implemented POTS devices (e.g., telephones and facsimile machines). Although this migration option is quick, all customers coupled to a DSLAM that is being brought offline need to be simultaneously switched to the ADL equipment that is replacing the DSLAM. Moreover, all customers being switched to the ADL equipment will likely require a Customer Premises Equipment (CPE) upgrade to ensure legacy customer POTS devices will operate with the ADL equipment at the CO. A second migration option involves replacing each individual DSL linecard housed in a DSLAM with an ADL enabled DSL linecard. This approach may be beneficial, as only those customers associated with the DSL linecard being replaced are affected. However, the second approach still necessitates simultaneously switching the customers associated with the DSL linecard to the ADL enabled DSL linecard. Moreover, exchanging individual DSL linecards is a manual process that is time consuming and involves significant man-hour costs. Finally, a third migration option involves replacing existing DSLAMs and POTS switches with ADL equipment, and moving individual customers over to the ADL equipment one by one. Currently, the third approach may only be accomplished via MDF reconfiguration. In particular, reconfiguration of an MDF to accommodate moving individual customers over to the ADL equipment may require mechanically rewiring individual customer connections to the ADL equipment. Such rewiring would be a prohibitively immense undertaking.